Fabrication method of semiconductor integrated circuit device

Abstract

The copper interconnect formed by the use of a damascene technique is improved in dielectric breakdown strength (reliability). During post-CMP cleaning, alkali cleaning, a deoxidizing process due to hydrogen annealing or the like, and acid cleaning are carried out in this order. After the post-CMP cleaning and before forming an insulation film for a cap film, hydrogen plasma and ammonia plasma processes are carried out on the semiconductor substrate. In this way, a copper-based buried interconnect is formed in an interlayer insulation film structured of an insulation material having a low dielectric constant.

What is claimed is:  
     
       1. A fabrication method of a semiconductor integrated circuit device, comprising the steps of: 
       (a) a step of forming a first insulation film on a main surface of a semiconductor substrate;  
       (b) a step of forming an interconnect opening in said first insulation film;  
       (c) a step of depositing a first conductor film for interconnect formation and a second conductor film based on copper for interconnect formation in that order on said first insulation film including an inside of said interconnect opening;  
       (d) a polishing process of polishing said first and second conductor films for interconnect formation thereby forming an interconnect in said interconnect opening;  
       (e) a process of carrying out a cleaning process on the semiconductor substrate after said polishing process;  
       (f) a process of carrying out a plasma process in a hydrogen atmosphere on the substrate after said cleaning process;  
       (g) a process of carrying out a plasma process in an ammonia atmosphere on the substrate after said cleaning process; and  
       (h) a process of depositing a second insulation film on said first insulation film and interconnect after said hydrogen gas plasma and ammonia gas plasma processes.  
     
     
       2. A fabrication method of a semiconductor integrated circuit device according to  claim 1 , wherein said cleaning process has a cleaning process using an alkali solution and a cleaning process using an acid solution. 
     
     
       3. A fabrication method of a semiconductor integrated circuit device according to  claim 2 , wherein said alkali solution includes aminoethanol. 
     
     
       4. A fabrication method of a semiconductor integrated circuit device according to  claim 2 , wherein said cleaning process has a step to carry out a cleaning process using said alkali solution, a deoxidizing process and a cleaning process using said acid solution in the order. 
     
     
       5. A fabrication method of a semiconductor integrated circuit device according to  claim 2 , having a step to carry out a deoxidizing process after said polishing process before said cleaning process. 
     
     
       6. A fabrication method of a semiconductor integrated circuit device according to  claim 2 , having a step to carry out a deoxidizing process after said polishing process before a cleaning process using said acid solution. 
     
     
       7. A fabrication method of a semiconductor integrated circuit device according to  claim 6 , wherein said deoxidizing process is to carry out a heating process on the semiconductor substrate in a hydrogen gas atmosphere. 
     
     
       8. A fabrication method of a semiconductor integrated circuit device according to  claim 6 , wherein said deoxidizing process is to carry out a hydrogen gas plasma process on the semiconductor substrate. 
     
     
       9. A fabrication method of a semiconductor integrated circuit device according to  claim 6 , wherein said dexidizing process is to carry out an ammonia gas plasma process on the semiconductor substrate. 
     
     
       10. A fabrication method of a semiconductor integrated circuit device according to  claim 1 , wherein said cleaning process has a step to carry out a cleaning process using an acid solution. 
     
     
       11. A fabrication method of a semiconductor integrated circuit device according to  claim 10 , having a step to carry out a deoxidizing process after said polishing step before said cleaning process using an acid solution. 
     
     
       12. A fabrication method of a semiconductor integrated circuit device according to  claim 1 , wherein a heating process is carried out on the semiconductor substrate in a deoxidizing gas atmosphere after said cleaning process and before said hydrogen gas plasma and ammonia gas plasma processes. 
     
     
       13. A fabrication method of a semiconductor integrated circuit device according to  claim 1 , wherein said second conductor film based on copper for interconnect formation is deposited by a plating technique. 
     
     
       14. A fabrication method of a semiconductor integrated circuit device according to  claim 1 , wherein said first insulation film is formed by an insulation film having a low dielectric constant. 
     
     
       15. A fabrication method of a semiconductor integrated circuit device according to  claim 1 , wherein said second insulation film is formed on said first insulation film and interconnect continuously without releasing to the air after said hydrogen gas plasma and ammonia gas plasma processes. 
     
     
       16. A fabrication method of a semiconductor integrated circuit device according to  claim 1 , wherein said second insulation film is formed by a silicon nitride film or silicon carbide film. 
     
     
       17. A fabrication method of a semiconductor integrated circuit device according to  claim 1 , wherein a process of said polishing step has a grit-free chemical mechanical polish. 
     
     
       18. A fabrication method of a semiconductor integrated circuit device, comprising the steps of: 
       (a) a step of forming a first insulation film on a main surface of a semiconductor substrate;  
       (b) a step of forming an interconnect opening in said first insulation film;  
       (c) a step of depositing a conductor film based on copper for interconnect formation on said first insulation film including an inside of said interconnect opening;  
       (d) a polishing process of polishing said conductor film based on copper for interconnect formation thereby forming an interconnect in said interconnect opening;  
       (e) a process of carrying out a cleaning process on the semiconductor substrate after said polishing process;  
       (f) a process of carrying out a plasma process in a hydrogen atmosphere on the substrate after said cleaning process;  
       (g) a process of carrying out a plasma process in an ammonia atmosphere on the substrate after said cleaning process; and  
       (h) a process of depositing a second insulation film on said first insulation film and interconnect after said hydrogen gas plasma and ammonia gas plasma processes.  
     
     
       19. A fabrication method of a semiconductor integrated circuit device, comprising the steps of: 
       (a) a step of forming a first insulation film on a main surface of a semiconductor substrate;  
       (b) a step of forming an interconnect opening in said first insulation film;  
       (c) a step of depositing a first conductor film for interconnect formation and a second conductor film based on copper for interconnect formation in that order on said first insulation film including an inside of said interconnect opening;  
       (d) a polishing process of polishing said first and second conductor films for interconnect formation thereby forming an interconnect in said interconnect opening;  
       (e) a process of carrying out a cleaning process using an alkali solution, a deoxidizing process and a cleaning process using an acid solution in that order on the semiconductor substrate after said polishing process; and  
       (f) a process of depositing a second insulation film on said first insulation film.  
     
     
       20. A fabrication method of a semiconductor integrated circuit device according to  claim 19 , wherein said alkali solution includes aminoethanol. 
     
     
       21. A fabrication method of a semiconductor integrated circuit device according to  claim 19 , wherein said deoxidizing process is to carry out a heating process on the semiconductor substrate in a hydrogen gas atmosphere. 
     
     
       22. A fabrication method of a semiconductor integrated circuit device according to  claim 19 , wherein said deoxidizing process is to carry out a hydrogen gas plasma process on the semiconductor substrate. 
     
     
       23. A fabrication method of a semiconductor integrated circuit device according to  claim 19 , wherein said deoxidizing process is to carry out an ammonia gas plasma process on the semiconductor substrate. 
     
     
       24. A fabrication method of a semiconductor integrated circuit device according to  claim 19 , wherein said second conductor film based on copper for interconnect formation is deposited by a plating technique. 
     
     
       25. A fabrication method of a semiconductor integrated circuit device according to  claim 19 , wherein said first insulation film is formed by an insulation film having a low dielectric constant. 
     
     
       26. A fabrication method of a semiconductor integrated circuit device according to  claim 19 , having a step to carry out an ammonia gas plasma process on the semiconductor substrate after said step (e) before the step of forming said second insulation film. 
     
     
       27. A fabrication method of a semiconductor integrated circuit device according to  claim 19 , wherein said second insulation film is formed by an SiN film, an SiC film or a SiOC film. 
     
     
       28. A fabrication method of a semiconductor integrated circuit device according to  claim 19 , wherein a process of said polishing step has a grit-free chemical mechanical polish. 
     
     
       29. A fabrication method of a semiconductor integrated circuit device, comprising the steps of: 
       (a) a step of forming a first insulation film on a main surface of a semiconductor substrate;  
       (b) a step of forming an interconnect opening in said first insulation film;  
       (c) a step of depositing a first conductor film for interconnect formation and a second conductor film based on copper for interconnect formation in that order on said first insulation film including an inside of said interconnect opening;  
       (d) a polishing process of polishing said first and second conductor films for interconnect formation thereby forming an interconnect in said interconnect opening;  
       (e) a process of carrying out a deoxidizing process and a process of using an acid solution in that order on the semiconductor substrate after said polishing process; and  
       (f) a process of depositing a second insulation film on said first insulation film and interconnect.  
     
     
       30. A fabrication method of a semiconductor integrated circuit device according to  claim 29 , wherein said deoxidizing process is to carry out a heating process on the semiconductor substrate in a hydrogen gas atmosphere. 
     
     
       31. A fabrication method of a semiconductor integrated circuit device according to  claim 29 , wherein said deoxidizing process is to carry out a hydrogen gas plasma process on the semiconductor substrate. 
     
     
       32. A fabrication method of a semiconductor integrated circuit device according to  claim 29 , wherein said deoxidizing process is to carry out an ammonia gas plasma process on the semiconductor substrate. 
     
     
       33. A fabrication method of a semiconductor integrated circuit device according to  claim 29 , wherein said second conductor film based on copper for interconnect formation is deposited by a plating technique. 
     
     
       34. A fabrication method of a semiconductor integrated circuit device according to  claim 29 , wherein said first insulation film is formed by an insulation film having a low dielectric constant. 
     
     
       35. A fabrication method of a semiconductor integrated circuit device according to  claim 29 , having a step to carry out an ammonia gas plasma process on the semiconductor substrate after the step (e) before a step of forming said second insulation film. 
     
     
       36. A fabrication method of a semiconductor integrated circuit device according to  claim 29 , wherein said second insulation film is formed by an SiN film, an SiC film or a SiOC film. 
     
     
       37. A fabrication method of a semiconductor integrated circuit device according to  claim 29 , wherein a process of said polishing step has a grit-free chemical mechanical polish. 
     
     
       38. A fabrication method of a semiconductor integrated circuit device, comprising the steps of: 
       (a) a step of forming a first insulation film on a main surface of a semiconductor substrate;  
       (b) a step of forming an interconnect opening in said first insulation film;  
       (c) a step of depositing a conductor film based on copper for interconnect formation on said first insulation film including an inside of said interconnect opening;  
       (d) a process of polishing said conductor film based on copper for interconnect formation thereby forming an interconnect in said interconnect opening;  
       (e) a process of carrying out a cleaning process using an alkali solution, a deoxidizing process and a cleaning process using an acid solution in that order on the semiconductor substrate after said polishing process; and  
       (f) a process of depositing a second insulation film on said first insulation film.  
     
     
       39. A fabrication method of a semiconductor integrated circuit device, comprising the steps of: 
       (a) a step of forming a first insulation film on a main surface of a semiconductor substrate;  
       (b) a step of forming an interconnect opening in said first insulation film;  
       (c) a step of depositing a conductor film based on copper for interconnect formation on said first insulation film including an inside of said interconnect opening;  
       (d) a process of polishing said conductor film based on copper for interconnect formation thereby forming an interconnect in said interconnect opening;  
       (e) a process of carrying out a deoxidizing process and a cleaning process using an acid solution on the semiconductor substrate of after said polishing process; and  
       (f) a process of depositing a second insulation film on said first insulation film.